feat: edge prompt + session resume implementation (#402)

- buildContinuationPrompt: incremental prompt for role re-entry
- buildHermesPrompt: dual-mode (initial vs continuation)
- session-cache: thread:role → hermes sessionId mapping
- HermesAcpClient.resume(): session/resume JSON-RPC
- Fallback: cache miss or resume fail → initial prompt
- UWF_NO_RESUME env to skip cache
- solve-issue.yaml: reviewer→developer edge prompt
- Tests updated for EvaluateResult + continuation prompt

Refs #402

packages/workflow-agent-kit/__tests__/build-continuation-prompt.test.ts

@@ -0,0 +1,70 @@
+import type { StepContext } from "@uncaged/workflow-protocol";
+import { describe, expect, test } from "vitest";
+import { buildContinuationPrompt } from "../src/build-continuation-prompt.js";
+
+const reviewerStep: StepContext = {
+  role: "reviewer",
+  output: { approved: false, comments: "Missing tests" },
+  detail: "2MXBG6PN4A8JR",
+  agent: "uwf-hermes",
+};
+
+const developerStep: StepContext = {
+  role: "developer",
+  output: { filesChanged: ["src/app.ts"], summary: "Initial fix" },
+  detail: "1VPBG9SM5E7WK",
+  agent: "uwf-hermes",
+};
+
+describe("buildContinuationPrompt", () => {
+  test("includes steps after the last matching role and the edge prompt", () => {
+    const steps: StepContext[] = [
+      developerStep,
+      reviewerStep,
+      {
+        role: "planner",
+        output: { plan: "revise approach" },
+        detail: "7BQST3VW9F2MA",
+        agent: "uwf-hermes",
+      },
+    ];
+
+    const result = buildContinuationPrompt(
+      steps,
+      "developer",
+      "The reviewer rejected your implementation. Read their feedback and fix the issues.",
+    );
+
+    expect(result).toContain("## What Happened Since Your Last Turn");
+    expect(result).toContain("### Step 2: reviewer");
+    expect(result).toContain("Missing tests");
+    expect(result).toContain("### Step 3: planner");
+    expect(result).toContain("## Moderator Instruction");
+    expect(result).toContain("The reviewer rejected your implementation.");
+    expect(result).not.toContain("Initial fix");
+  });
+
+  test("uses all steps when the role has not run before", () => {
+    const result = buildContinuationPrompt(
+      [developerStep, reviewerStep],
+      "planner",
+      "Continue from the reviewer feedback.",
+    );
+
+    expect(result).toContain("### Step 1: developer");
+    expect(result).toContain("### Step 2: reviewer");
+    expect(result).toContain("Continue from the reviewer feedback.");
+  });
+
+  test("still includes moderator instruction when there are no intervening steps", () => {
+    const result = buildContinuationPrompt(
+      [developerStep],
+      "developer",
+      "Please revise your work.",
+    );
+
+    expect(result).not.toContain("## What Happened Since Your Last Turn");
+    expect(result).toContain("## Moderator Instruction");
+    expect(result).toContain("Please revise your work.");
+  });
+});

packages/workflow-agent-kit/src/build-continuation-prompt.ts

@@ -0,0 +1,53 @@
+import type { StepContext } from "@uncaged/workflow-protocol";
+
+function formatStep(step: StepContext, stepNumber: number): string {
+  return [
+    `### Step ${stepNumber}: ${step.role}`,
+    `Output: ${JSON.stringify(step.output)}`,
+    `Agent: ${step.agent}`,
+  ].join("\n");
+}
+
+function findLastRoleIndex(steps: StepContext[], role: string): number {
+  for (let i = steps.length - 1; i >= 0; i--) {
+    const step = steps[i];
+    if (step !== undefined && step.role === role) {
+      return i;
+    }
+  }
+  return -1;
+}
+
+/**
+ * Build a continuation prompt for a role re-entry.
+ *
+ * Finds the most recent step for `role`, collects everything after it as context,
+ * and appends the moderator edge prompt as the instruction.
+ */
+export function buildContinuationPrompt(
+  steps: StepContext[],
+  role: string,
+  edgePrompt: string,
+): string {
+  const lastIndex = findLastRoleIndex(steps, role);
+  const sinceSteps = lastIndex >= 0 ? steps.slice(lastIndex + 1) : steps;
+
+  const parts: string[] = [];
+
+  if (sinceSteps.length > 0) {
+    parts.push("## What Happened Since Your Last Turn");
+    const baseStepNumber = lastIndex >= 0 ? lastIndex + 2 : 1;
+    for (let i = 0; i < sinceSteps.length; i++) {
+      const step = sinceSteps[i];
+      if (step === undefined) {
+        continue;
+      }
+      parts.push("");
+      parts.push(formatStep(step, baseStepNumber + i));
+    }
+    parts.push("");
+  }
+
+  parts.push("## Moderator Instruction", "", edgePrompt);
+  return parts.join("\n");
+}

packages/workflow-agent-kit/src/index.ts

@@ -1,3 +1,4 @@
+export { buildContinuationPrompt } from "./build-continuation-prompt.js";
 export { buildOutputFormatInstruction } from "./build-output-format-instruction.js";
 export { buildRolePrompt } from "./build-role-prompt.js";
 export type { BuildContextMeta } from "./context.js";
@@ -11,7 +12,7 @@ export {
 export type { FrontmatterFastPathResult } from "./frontmatter.js";
 export { tryFrontmatterFastPath } from "./frontmatter.js";
 export { createAgent } from "./run.js";
-export { getConfigPath, getEnvPath, loadWorkflowConfig } from "./storage.js";
+export { getConfigPath, getEnvPath, loadWorkflowConfig, resolveStorageRoot } from "./storage.js";
 export type {
   AgentContext,
   AgentContinueFn,